408 Spirochaetes of Tapes aureus 
with iron-haematoxylin, except Fig. 47, which was stained with Delafield’s haema- 
toxylin. 
Figs. 49—52 illustrate transverve division. 
Fig. 49. Parasite with slightly tapering ends about to divide. A slightly arched 
constriction appears at the centre, which is unstained internally. By its division 
the parent produces forms of the type shown in Fig. 16, though naturally shorter at 
first. 
Fig. 50. Parasite with slightly constricted unstained area in the middle. Division takes 
place at the unstained area. 
Fig. 51. Spirochaete about to divide at the abrupt constriction in the middle, producing 
daughter forms with more or less rounded ends, like that shown in Fig. 26. 
Fig. 52. Spirochaete with very tenuous centre, just about to produce individuals with 
pointed ends, like that shown in Fig. 17. 
Fig. 53. Parasite drawn to show the extreme flexibility of Spirochaetes. This form, 
originally resembling that drawn in Fig. 15, has become coiled in a most complicated 
manner at one end, resulting in the production of a “pseudo-cyst.” 
Fig. 54. Transverse sections of Spirochaetes from serial sections of an infected crystalline 
style of Tapes aureus, x 1750 approximately. 
a. Section of Spirochaete passing between the chromatin bars. Membrane 
contracted close to the body, and seen as a granular projection on the right 
of the body. 
b. Section of larger Spirochaete, passing through chromatin bar. Membrane seen 
as a lateral extension of the periplast. 
c. Section of Spirochaete, passing through edge of chromatin bar. Membrane 
shown as periplast extension. 
d. Section of broad Spirochaete through bar of chromatin. Thickened chromatic 
edge of membrane seen. 
